pdns/devpollmplexer.cc

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25 /*
  26  * NOTE: sys/devpoll.h relies on sigset_t being already defined so we need
  27  * to include sys/signal.h *before* including sys/devpoll.h.
  28  */
  29 #include <sys/signal.h>
  30 #include <sys/devpoll.h>
  31 #include "mplexer.hh"
  32 #include "sstuff.hh"
  33 #include <iostream>
  34 #include <unistd.h>
  35 #include "misc.hh"
  36 #include "syncres.hh"
  37
  38 #include "namespaces.hh"
  39 #include "namespaces.hh"
  40
  41 class DevPollFDMultiplexer : public FDMultiplexer
  42 {
  43 public:
  44   DevPollFDMultiplexer();
  45   virtual ~DevPollFDMultiplexer()
  46   {
  47     close(d_devpollfd);
  48   }
  49
  50   virtual int run(struct timeval* tv);
  51
  52   virtual void addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter);
  53   virtual void removeFD(callbackmap_t& cbmap, int fd);
  54   string getName()
  55   {
  56     return "/dev/poll";
  57   }
  58 private:
  59   int d_devpollfd;
  60 };
  61
  62
  63 static FDMultiplexer* makeDevPoll()
  64 {
  65   return new DevPollFDMultiplexer();
  66 }
  67
  68 static struct DevPollRegisterOurselves
  69 {
  70   DevPollRegisterOurselves() {
  71     FDMultiplexer::getMultiplexerMap().insert(make_pair(0, &makeDevPoll)); // priority 0!
  72   }
  73 } doItDevPoll;
  74
  75
  76 //int DevPollFDMultiplexer::s_maxevents=1024;
  77 DevPollFDMultiplexer::DevPollFDMultiplexer()
  78 {
  79   d_devpollfd=open("/dev/poll", O_RDWR);
  80   if(d_devpollfd < 0)
  81     throw FDMultiplexerException("Setting up /dev/poll: "+stringerror());
  82
  83 }
  84
  85 void DevPollFDMultiplexer::addFD(callbackmap_t& cbmap, int fd, callbackfunc_t toDo, const funcparam_t& parameter)
  86 {
  87   accountingAddFD(cbmap, fd, toDo, parameter);
  88
  89   struct pollfd devent;
  90   devent.fd=fd;
  91   devent.events= (&cbmap == &d_readCallbacks) ? POLLIN : POLLOUT;
  92   devent.revents = 0;
  93
  94   if(write(d_devpollfd, &devent, sizeof(devent)) != sizeof(devent)) {
  95     cbmap.erase(fd);
  96     throw FDMultiplexerException("Adding fd to /dev/poll/ set: "+stringerror());
  97   }
  98 }
  99
 100 void DevPollFDMultiplexer::removeFD(callbackmap_t& cbmap, int fd)
 101 {
 102   if(!cbmap.erase(fd))
 103     throw FDMultiplexerException("Tried to remove unlisted fd "+std::to_string(fd)+ " from multiplexer");
 104
 105   struct pollfd devent;
 106   devent.fd=fd;
 107   devent.events= POLLREMOVE;
 108   devent.revents = 0;
 109
 110   if(write(d_devpollfd, &devent, sizeof(devent)) != sizeof(devent)) {
 111     cbmap.erase(fd);
 112     throw FDMultiplexerException("Removing fd from epoll set: "+stringerror());
 113   }
 114 }
 115
 116 int DevPollFDMultiplexer::run(struct timeval* now)
 117 {
 118   if(d_inrun) {
 119     throw FDMultiplexerException("FDMultiplexer::run() is not reentrant!\n");
 120   }
 121   struct dvpoll dvp;
 122   dvp.dp_nfds = d_readCallbacks.size() + d_writeCallbacks.size();
 123   dvp.dp_fds = new pollfd[dvp.dp_nfds];
 124   dvp.dp_timeout = 500;
 125   int ret=ioctl(d_devpollfd, DP_POLL, &dvp);
 126   gettimeofday(now,0); // MANDATORY!
 127
 128   if(ret < 0 && errno!=EINTR) {
 129     delete[] dvp.dp_fds;
 130     throw FDMultiplexerException("/dev/poll returned error: "+stringerror());
 131   }
 132
 133   if(ret < 1) { // thanks AB!
 134     delete[] dvp.dp_fds;
 135     return 0;
 136   }
 137
 138   d_inrun=true;
 139   for(int n=0; n < ret; ++n) {
 140     d_iter=d_readCallbacks.find(dvp.dp_fds[n].fd);
 141
 142     if(d_iter != d_readCallbacks.end()) {
 143       d_iter->second.d_callback(d_iter->first, d_iter->second.d_parameter);
 144       continue; // so we don't refind ourselves as writable!
 145     }
 146     d_iter=d_writeCallbacks.find(dvp.dp_fds[n].fd);
 147
 148     if(d_iter != d_writeCallbacks.end()) {
 149       d_iter->second.d_callback(d_iter->first, d_iter->second.d_parameter);
 150     }
 151   }
 152   delete[] dvp.dp_fds;
 153   d_inrun=false;
 154   return 0;
 155 }
 156
 157 #if 0
 158 void acceptData(int fd, funcparam_t& parameter)
 159 {
 160   cout<<"Have data on fd "<<fd<<endl;
 161   Socket* sock=funcparam_t_cast<Socket*>(parameter);
 162   string packet;
 163   IPEndpoint rem;
 164   sock->recvFrom(packet, rem);
 165   cout<<"Received "<<packet.size()<<" bytes!\n";
 166 }
 167
 168
 169 int main()
 170 {
 171   Socket s(AF_INET, SOCK_DGRAM);
 172
 173   IPEndpoint loc("0.0.0.0", 2000);
 174   s.bind(loc);
 175
 176   DevPollFDMultiplexer sfm;
 177
 178   sfm.addReadFD(s.getHandle(), &acceptData, &s);
 179
 180   for(int n=0; n < 100 ; ++n) {
 181     sfm.run();
 182   }
 183   sfm.removeReadFD(s.getHandle());
 184   sfm.removeReadFD(s.getHandle());
 185 }
 186 #endif
 187
 188